Plants are rich with light receptors, but it has been unclear by the depths of the roots on how plants are capable in channeling light down there. Scientists finally unraveled this deep mystery.
We might have underestimated plants' capability in directing and using sunlight's energy all over its structure. Light receptors in plants run from its leaves, stems, flowers and even down to its roots. How plants sense light from the deep ends of its structure and down within the dark earth - that has been unclear.
Hyo-Jun Lee of Seoul National University in South Korea and his team studied Arabidopsis thaliana,
a small flowering weed to understand this phenomenon.
They found that the plants' stems function like a fibre-optic cable that sends light down to its root receptors called phytochromes. The question lies on whether the channeling of light was possible through a chemical process or direct light transmission.
To find that out, Lee's team devised a detector to tell them how the process worked within the plants' system. They also had to attach a direct light source to the stem. The detector they attached at the end of the stem confirmed that light indeed was directly transmitted through.
They also tested the if injecting the Arabidopsis thaliana with the signalling chemicals could spur its root growth. The result was negative.
Phytochromes are sensitive to red or far-red light which is usually regarded as the region between 710 and 850 nm wavelength.
Dr John Runions/Science Photo Library
"The light’s intensity would be too low for creatures in the soil to see it illuminating the roots, or for bacteria to use it for photosynthesis." Lee says. He added that piping sunlight down the stems is common method to optimize root growth.
Mike Haydon at the University of Melbourne, agrees saying that light signalling is faster than chemical signalling.
Haydon added that it is important to note that Lee's study only investigated limited amount of chemicals to confirm the relationship between light, stems and roots.
The study is published in a journal Science
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